Impact of Gurney Flaplike Strips on the Aerodynamic and Vortex Flow Characteristic of a Reverse Delta Wing

The impact of Gurney flaplike strips, of different geometric configurations and heights, on the aerodynamic characteristics and the tip vortices generated by a reverse delta wing (RDW) was investigated via force-balance measurement and particle image velocimetry (PIV). The addition of side-edge strips (SESs) caused a leftward shift of the lift curve, resembling a conventional trailing-edge flap. The large lift increment overwhelmed the corresponding drag increase, thereby leading to an improved lift-to-drag ratio compared to the baseline wing. The lift and drag coefficients were also found to increase with the strip height. The SES-equipped wing also produced a strengthened vortex compared to its baseline wing counterpart. The leading-edge strips (LESs) were, however, found to persistently produce a greatly diffused vortex flow as well as a small-than-baseline-wing lift in the prestall α regime. The downward LES delivered a delayed stall and an increased maximum lift coefficient compared to the baseline wing. The LESs provide a potential wingtip vortex control alternative, while the SESs can enhance the aerodynamic performance of the RDW.

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Effect of Leading-Edge Bulges on Aerodynamic Characteristics of Bionic Wingsail

10.3233/atde210340 ◽

2021 ◽

Author(s):

Chen Li ◽

Peiting Sun ◽

Hongming Wang

Keyword(s):

Stokes Equations ◽

Lift Coefficient ◽

Leading Edge ◽

Aerodynamic Characteristics ◽

Navier Stokes ◽

Suction Surface ◽

Ansys Fluent ◽

Navier Stokes Equations ◽

Extension Direction ◽

Lift And Drag

The leading-edge bulges along the extension direction are designed on the marine wingsail. The height and the spanwise wavelength of the protuberances are 0.1c and 0.25c, respectively. At Reynolds number Re=5×105, the Reynolds Averaged Navier-Stokes equations are applied to the simulation of the wingsail with the bulges thanks to ANSYS Fluent finite-volume solver based on the SST K-ω models. The grid independence analysis is carried out with the lift and drag coefficients of the wingsail at AOA = 8° and AOA=20°. The results show that while the efficiency of the wingsail is reduced by devising the leading-edge bulges before stall, the bulges help to improve the lift coefficient of the wingsail when stalling. At AOA=22° under the action of the leading-edge tubercles, a convective vortex is formed on the suction surface of the modified wingsail, which reduces the flow loss. So the bulges of the wingsail can delay the stall.

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Aerodynamic characteristics of dragonfly wing sections compared with technical aerofoils

Journal of Experimental Biology ◽

10.1242/jeb.203.20.3125 ◽

2000 ◽

Vol 203 (20) ◽

pp. 3125-3135 ◽

Cited By ~ 3

Author(s):

A.B. Kesel

Keyword(s):

Negative Pressure ◽

Leading Edge ◽

Longitudinal Axis ◽

Aerodynamic Characteristics ◽

Force Balance ◽

Flat Plates ◽

Cross Sectional ◽

Drag Coefficients ◽

Balance System ◽

Lift And Drag

During gliding, dragonfly wings can be interpreted as acting as ultra-light aerofoils which, for static reasons, have a well-defined cross-sectional corrugation. This corrugation forms profile valleys in which rotating vortices develop. The cross-sectional configuration varies greatly along the longitudinal axis of the wing. This produces different local aerodynamic characteristics. Analyses of the C(L)/C(D) characteristics, where C(L) and C(D) are the lift and drag coefficients, respectively (at Reynolds numbers Re of 7880 and 10 000), using a force balance system, have shown that all cross-sectional geometries have very low drag coefficients (C(D, min)<0.06) closely resembling those of flat plates. However, the wing profiles, depending upon their position along the span length, attain much higher lift values than flat plates. The orientation of the leading edge does not play an important role. The detectable lift forces can be compared with those of technical wing profiles for low Re numbers. Pressure measurements (at Re=9300) show that, because of rotating vortices along the chord length, not only is the effective profile form changed, but the pressure relationship on the profile is also changed. Irrespective of the side of the profile, negative pressure is produced in the profile valleys, and net negative pressure on the upper side of the profile is reached only at angles of attack greater than 0 degrees. These results demonstrate the importance of careful geometrical synchronisation as an answer to the static and aerodynamic demands placed upon the ultra-light aerofoils of a dragonfly.

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Effect of Shapes and Turbulent Inlet Flow to Vortices on Delta Wings

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.889.434 ◽

2019 ◽

Vol 889 ◽

pp. 434-439

Author(s):

Ngoc Khanh Tran ◽

Van Khang Nguyen ◽

Phu Khanh Nguyen ◽

Thi Kim Dung Hoang ◽

Van Quang Dao

Keyword(s):

Turbulence Intensity ◽

Delta Wing ◽

Lift Coefficient ◽

Pressure Coefficient ◽

Leading Edge ◽

Aerodynamic Characteristics ◽

Delta Wings ◽

Ansys Fluent ◽

Inlet Flow ◽

Stall Angle

This paper aims to estimate the effect of turbulent inlet flow to vortices on Delta wing with four different turbulence intensity from 0.5% to 15% and the effect of taper ratios to aerodynamic characteristics of Delta wings with four taper ratios: 0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7. The main purpose of this paper is to find out the formation, development, and breakdown of vortices on Delta wings when changing taper ratios and turbulence intensity thence determining the center of vortices with the range of attack angles from 5o to 40o in low velocities about 2.5 m/s. This research uses Delta wing models with a 40o swept-back leading edge, the root chord length 150 mm, and a thickness 5 mm. The problem is simulated by using ANSYS fluent and experiment in the subsonic wind tunnel to compare and validate results. The Delta wing models are meshed by using ICEM to improve the mesh quality and using the turbulence model for low Reynolds number flows Transition SST (4 equations) to calculate aerodynamic characteristics such as lift coefficient, drag coefficient, pressure coefficient... find the paths which connect centers of the vortices, and show the contours of pressures and velocities to evaluate the change of centers of the vortices. The results showed that the two vortices grow up and tend to move inward when the attack angle increase, the vortices are broken strongly in high attack angles, the aerodynamic quality of Delta wings change insignificantly when changing turbulent intensity at inlet. This research also carried out that the stall angle increase when increasing the taper ratio.

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Cavity for Flow Control and Performance Improvement of Airfoil

10.1115/gtindia2021-76415 ◽

2021 ◽

Author(s):

Anand Verma ◽

Bastav Borah ◽

Vinayak Kulkarni

Keyword(s):

Moving Boundary ◽

Flow Analysis ◽

Leading Edge ◽

Aerodynamic Characteristics ◽

Suction Surface ◽

Confined Spaces ◽

Steady Simulation ◽

And Performance ◽

Lift And Drag ◽

Fluid Flow Analysis

Abstract The fluid flow analysis over a cambered airfoil having three different cavity locations on the suction surface is reported in this paper. The Elliptical cavity is created at LE, MC, and TE along chordwise locations from the leading to trailing edge. In this regard, the steady simulation is carried out in the Fluent at Reynolds number of 105 based on their chord length. The lift and drag characteristics for clean and cavities airfoil are investigated at different angles of attack. For the clean airfoil, the stall point is observed at 18°. The presence of a cavity improves the stall and aerodynamic characteristics of airfoil. It has been seen that the lift and drag coefficients for pre-stalled or lower angles are nearly similar to clean and cavity at MC or TE positions. For the post-stall point, the improvement in the aerodynamic performance is seen for the cavity at MC or TE. The cavity placed at LE produces lower lift and higher drag characteristics against other configuration models. The overall cavity effect for the flow around the airfoil is that it creates vortices, thereby re-energizes the slower moving boundary layer and delays the flow separation in the downstream direction. The outcomes of this analysis are suggested that the cavity at a position before the mid chord from the leading edge does not improve the performance of the airfoil. Though vortex is formed in the confined spaces but it is unable to reattach the flow towards the downstream direction of an airfoil.

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Effects of leading-edge bevel angle on the aerodynamic forces of a non-slender 50° delta wing

The Aeronautical Journal ◽

10.1017/s0001924000000828 ◽

2005 ◽

Vol 109 (1098) ◽

pp. 403-407 ◽

Cited By ~ 7

Author(s):

J. J. Wang ◽

S. F. Lu

Keyword(s):

Delta Wing ◽

Lift Coefficient ◽

Leading Edge ◽

Relative Thickness ◽

Aerodynamic Performances ◽

Stall Angle ◽

Drag Ratio ◽

Low Speed Wind Tunnel ◽

Lift To Drag Ratio ◽

Blunt Leading Edge

Abstract The aerodynamic performances of a non-slender 50° delta wing with various leading-edge bevels were measured in a low speed wind tunnel. It is found that the delta wing with leading-edge bevelled leeward can improve the maximum lift coefficient and maximum lift to drag ratio, and the stall angle of the wing is also delayed. In comparison with the blunt leading-edge wing, the increment of maximum lift to drag ratio is 200%, 98% and 100% for the wings with relative thickness t/c = 2%, t/c = 6.7% and t/c = 10%, respectively.

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Prediction of Delta Wing Leading-Edge Vortex Circulation and Lift-Curve Slope

Journal of Aircraft ◽

10.2514/2.2193 ◽

1997 ◽

Vol 34 (3) ◽

pp. 450-452 ◽

Cited By ~ 23

Author(s):

Lance W. Traub

Keyword(s):

Delta Wing ◽

Leading Edge ◽

Leading Edge Vortex ◽

Lift Curve ◽

Edge Vortex

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Effect of a centerbody on the vortex flow of a double-delta wing with leading edge extension

Aerospace Science and Technology ◽

10.1016/j.ast.2009.11.004 ◽

2010 ◽

Vol 14 (1) ◽

pp. 11-18 ◽

Cited By ~ 7

Author(s):

Myong Hwan Sohn ◽

Jo Won Chang

Keyword(s):

Vortex Flow ◽

Delta Wing ◽

Leading Edge ◽

Double Delta Wing ◽

Edge Extension ◽

Leading Edge Extension

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Vortex flow and lift generation of a non-slender reverse delta wing

Proceedings of the Institution of Mechanical Engineers Part G Journal of Aerospace Engineering ◽

10.1177/0954410016671342 ◽

2016 ◽

Vol 231 (13) ◽

pp. 2438-2451

Author(s):

T Lee ◽

LS Ko

Keyword(s):

Particle Image Velocimetry ◽

Lift Force ◽

Vortex Flow ◽

Particle Image ◽

Delta Wing ◽

Lower Surface ◽

Force Balance ◽

Flow Parameters ◽

Image Velocimetry ◽

Spanwise Vortex

The vortex flow and lift force generated by a 50°-sweep non-slender reverse delta wing were investigated via particle image velocimetry, together with flow visualization and force balance measurement, at Re = 11,000. The non-slender reverse delta wing produced a delayed stall but a lower lift compared to its delta wing counterpart. The stalling mechanism was also found to be triggered by the disruption of the multiple spanwise vortex filaments developed over the upper wing surface. The vortex flowfield was, however, characterized by the co-existence of reverse delta wing vortices and multiple shear-layer vortices. The outboard location of the reverse delta wing vortex further implies that the lift force is mainly generated by the wing lower surface while the upper surface acts as a wake generator. The spatial progression of the flow parameters of the vortex generated by the non-slender reverse delta wing as a function of α was also discussed.

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